An organic electroluminescence device (hereinafter, being occasionally abbreviated as EL) is a spontaneous light emitting device which utilizes such a principle that a fluorescent substance emits light by virtue of recombination energy of holes injected from an anode and electrons injected from a cathode by an application of an electric field.
The organic EL devices are each one display form for a display or the like, and are promising new-generation displays because of such characteristics as described below. Each of the organic EL devices has a wide view angle, can be thinned, and shows good motion picture responsiveness. Since the rollout of the organic EL devices by Tang et al. in 1987, assorted materials for the organic EL devices have been disclosed. Of those, light emitting materials that contribute to light emission each directly affect durability (hereinafter, being occasionally referred to as “lifetime”) and luminous efficiency, and hence the development of a material that realizes a long-lifetime, high-efficiency organic EL device has been requested.
Devices each using a fused polycyclic compound in an electron transporting layer or light emitting layer have been disclosed in recent years. A fused polycyclic compound obtained by introducing a 4-(9-phenanthryl)phenyl group, a biphenylyl group, a terphenyl group, a dibenzofuryl group, a dibenzothiophenyl group, a dibenzodioxynyl group, a dibenzodithiinyl group, a dibenzoxythiinyl group, a benzophenonyl group, or the like to the 10-position of the anthracenylene group of a substituted or unsubstituted 9-(9-phenanthryl)anthracene has been proposed as a compound having an anthracene skeleton (Patent Document 1).
A fused polycyclic compound in which the 9-position of a substituted or unsubstituted phenanthryl group and the 9-position of an anthracenylene group are directly bonded to each other has been proposed (Patent Document 2).
In addition, a fused polycyclic compound in which a 9-phenanthryl group is bonded to the 9-position of an anthracenylene group through a phenylene group has been proposed (Patent Document 3).
Further, a fused polycyclic compound in which the 9-position of a substituted or unsubstituted phenanthryl group and the 9-position of an anthracenylene group are bonded to each other through a naphthylene group has been proposed (Patent Document 4).
A compound in which the 9- and 10-positions of an anthracenylene group are each substituted with a 2-phenanthryl group (Patent Document 5), a compound in which the 2- and 7-positions of phenanthrene are each substituted with an anthracenylene group (Patent Document 6), and a compound in which the 9-position of an anthracenylene group is substituted with a 9-phenanthryl group (Patent Document 7) have been disclosed.
Further, tris [10-(9-phenanthryl) anthracen-9-yl]benzene as a starburst fused polycyclic compound (Patent Document 8) has been disclosed.
In addition, a fused polycyclic compound obtained by introducing a 4-(9-phenanthryl)phenyl group, a biphenylyl group, a terphenyl group, a dibenzofuryl group, a dibenzothiophenyl group, a dibenzodioxynyl group, a dibenzodithiinyl group, a dibenzoxythiinyl group, a benzophenonyl group, or the like to the 10-position of the anthracene nucleus of a substituted or unsubstituted 9-(9-phenanthryl)anthracene has been investigated (Patent Document 9).
In addition, a 3-phenanthrylanthracene derivative containing carbazole (Patent Document 10) has been disclosed.
An improvement in material performance has been observed in any one of those material systems. At present, however, none of the systems has achieved performance sufficient for commercialization because an optical output with additionally high luminance or additionally high conversion efficiency is needed. In addition, the systems each still involve a large number of problems in terms of durability such as a change over time due to long-term use and deterioration due to, for example, an atmospheric gas containing oxygen or moisture. Therefore, durability as well as additionally high luminous efficiency has been requested at present.
Patent Document 1: WO 2004/018587
Patent Document 2: JP-A-2005-041843
Patent Document 3: WO 2005/054162
Patent Document 4: WO 2005/061656
Patent Document 5: U.S. Pat. No. 5,935,721
Patent Document 6: WO 2006/039982
Patent Document 7: US 2005/089717
Patent Document 8: JP-A-2002-329580
Patent Document 9: JP-A-2005-314239
Patent Document 10: WO 2005/113531